Wideband waveform design for relay cognitive network

In this paper, wideband waveform design for relay cognitive network will be presented. There is one transmitter, several relay nodes and one or several receivers in cognitive network. Assume there is no direct communication link between the transmitter and the receiver. We would like to jointly design the transmitted waveform and the FIR filters at the relay nodes such that the received signal to noise ratio (SNR) can beat the threshold derived from quality of service (QoS). However the general formulation of this problem is not convex. It is hard to find the global optimal solutions for the transmitted waveform plus the relay FIR filters. Thus a semidefinite programming (SDP)-based iterative method is proposed in this paper to obtain the feasible solution and the received SNR can still be guaranteed. Numerical results will be provided to evaluate the performance of wideband waveform design in the context of relay cognitive network.